The Angstrom Project is using a distributed network of two-meter class telescopes to conduct a high cadence pixel-lensing survey of the bulge of the Andromeda Galaxy ( M31 ) .
With the expansion of global telescope network , the detection efficiency of pixel-lensing surveys is rapidly improving .
In this paper , we estimate the detection rate of binary lens events expected from high-cadence pixel-lensing surveys toward M31 such as the Angstrom Project based on detailed simulation of events and application of realistic observational conditions .
Under the conservative detection criteria that only high signal-to-noise caustic-crossing events with long enough durations between caustic crossings can be firmly identified as binary lens events , we estimate that the rate would be \Gamma _ { b } \sim ( 7 - 15 ) f _ { b } ( N / 50 ) per season , where f _ { b } is the fraction of binaries with projected separations of 10 ^ { -3 } { AU } < \tilde { d } < 10 ^ { 3 } { AU } out of all lenses and N is the rate of stellar pixel-lensing events .
We find that detected binaries would have mass ratios distributed over a wide range of q \gtrsim 0.1 but with separations populated within a narrow range of 1 { AU } \lesssim \tilde { d } \lesssim 5 { AU } .
Implementation of an alert system and subsequent follow-up observations would be important not only for the increase of the binary lens event rate but also for the characterization of lens matter .